 (def map-context
   (reify
     p/Context
-    (-get-level [_] ctx/+level-default+)
-
     p/Semigroup
     (-mappend [_ sv sv']
       (merge sv sv'))

(def sum-monoid
  (reify
    p/Context
    (-get-level [_] ctx/+level-default+)

    p/Semigroup
    (-mappend [_ sv sv']
      (+ sv sv'))

(def vector-context
  (reify
    p/Context
    p/Semigroup
    (-mappend [_ sv sv']
      (into sv sv'))
